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Lennox G513 HVAC Units

I have a pair of Lennox G513 HVAC units cooling the main and second floors
of a residence. The compressor/condenser cabinets are mounted on a concrete
pad positioned away from the main building. The evaporators are integrated
within the 60's era custom, heavy gauge, commercial quality ductwork for the
three furnaces in the residence.

The main floor's compressor is in need of repair/replacement.

I have been told that these units are obsolete, their refrigerant has been
banned and parts are NLA - the recommendation is to replace them with
modern units.

I'm certain that it CAN be repaired, but SHOULD it be is the better question.

It has had a good life, put that dog down and put a newer, higher efficiency unit in.

Let's explore this prospect of changing out the existing units for newer, higher
efficiency units.

Is doing so merely a matter of replacing the compressor/condensor cabinets
on the pads outside the home and connecting them to the existing refrigeration
lines and evaporator units mounted inside on the furnaces?) Or do newer units
require different lines and evaporators?

If new lines are required, is there some means of trenchless replacement that
will pass the new lines under a paved area that extends some distance out
from the house foundation? Is there a way to snake the lines through the
rear foundation wall and forward through the walls/ceiling of a developed
basement into the mechanical room at the front of the home?

If new evaporators are required, can they be fitted in place of the existing
evaporators while retaining the present furnaces and ductwork depicted below?
What chance is there that after the job is underway and it is too late to
restore the initial configuration that word will come from the contractor that
more work than originally anticipated is required?

its time for that whole mess to head to the scrap yard, that equipment has far exceeded it's useful life.

Mess ? Why "mess" ?

I looked back a bit in your previous posts for recent photo examples of current
best practices without success. However, judging by what appears in threads
posted by other owners, current practice comes up short compared to what
appears in the photos above.

And what determines useful life? Those furnaces are just some sheet metal
boxes with motors, blowers, valves, burners and heat exchangers inside.
It is not uncommon here for ambiant temperatures to drop below -40ºF
and then remain there for ten to fourteen days each January - the equipment
shown works on demand and keeps the building and occupants comfortable
when that happens. It does so at a fuel and electrical cost that is tolerable.

As I anticipate will be confirmed about the A/C units, changing out the
furnaces in favour of current equipment will not be a trivial matter. Far
from just an R&R of suitably sized furnaces, with THIS home, there will
need to be a wholesale redesign of the fresh and combustion air
supply/venting with attendent demolition and renovation involving numerous
trades to accomplish same, along with headaches about how to deal with
cosmetic issues regarding location of the chimneys and so on.

In due course, that day will come. However, it seems a bit premature to
set off on that expensive course of action when all I appear to need is a
compressor replacement for the m/f unit.

Originally Posted by jpsmith1cm

I'm certain that it CAN be repaired, but SHOULD it be is the better question.

What is the expected lifespan of this unit?

I am at a stage in life where there is every chance that I will be looking for
different lodgings within ten years. Recouping the kind of investment required
by a wholesale refit through personal enjoyment or added resale just doesn't
seem likely to happen.

My goal is to restore the functionality of the m/f unit so that for the 30 to 45
days of each year that we experience 80ºF+ days with high humidity the 2nd
floor unit is not having to carry the entire cooling burden, I can relax rules
against oven, d-washer and dryer use during daylight hours and there is back-up
refrigeration on hand in the event that a problem brings down the 2nd floor unit.

If your service company wanted to they could find a compressor either a oe or a retrofit r 22 refrigerant is plentiful , although you would better in the long run to replace the complete system .the situation you will find at sale time is buyers will want newer equipment i have replaced units that because the new buyers home inspector recommended it due to age and the sellers never got to use the new units

I looked back a bit in your previous posts for recent photo examples of current
best practices without success. However, judging by what appears in threads
posted by other owners, current practice comes up short compared to what
appears in the photos above.

And what determines useful life? Those furnaces are just some sheet metal
boxes with motors, blowers, valves, burners and heat exchangers inside.
It is not uncommon here for ambiant temperatures to drop below -40ºF
and then remain there for ten to fourteen days each January - the equipment
shown works on demand and keeps the building and occupants comfortable
when that happens. It does so at a fuel and electrical cost that is tolerable.

As I anticipate will be confirmed about the A/C units, changing out the
furnaces in favour of current equipment will not be a trivial matter. Far
from just an R&R of suitably sized furnaces, with THIS home, there will
need to be a wholesale redesign of the fresh and combustion air
supply/venting with attendent demolition and renovation involving numerous
trades to accomplish same, along with headaches about how to deal with
cosmetic issues regarding location of the chimneys and so on.

In due course, that day will come. However, it seems a bit premature to
set off on that expensive course of action when all I appear to need is a
compressor replacement for the m/f unit.

I am at a stage in life where there is every chance that I will be looking for
different lodgings within ten years. Recouping the kind of investment required
by a wholesale refit through personal enjoyment or added resale just doesn't
seem likely to happen.

My goal is to restore the functionality of the m/f unit so that for the 30 to 45
days of each year that we experience 80ºF+ days with high humidity the 2nd
floor unit is not having to carry the entire cooling burden, I can relax rules
against oven, d-washer and dryer use during daylight hours and there is back-up
refrigeration on hand in the event that a problem brings down the 2nd floor unit.

Thank you for the replies.

.

maybe "mess" was a bad choice of word......... the system is 50 years old and parts availabilty for those furnaces is almost non existant from Lennox. in the long run you would be much better off changing out the system rather than putting money into repairs.

"Hey Lama, hey, how about a little something, you know, for the effort." And he says, "there won't be any money, but when you die, on your deathbed, you will receive total consciousness." So I got that goin' for me, which is nice. - Carl Spackler

You might want to book an appointment with your optometrist. Here, take
a closer look ...

I know that these images don't include the critical areas where cracks form
in exchangers, but I am not inclined to go to the trouble of getting up in there
just to rebutt your presumption. As one of the forum's Pros, you will recognize
what you are looking at here.

catmanacman and beenthere, thank you for your more reasoned support and advice.

Regarding the evaporator coil and refrigerant lines. I had been led to believe that
newer equipment runs at higher pressures and that consequently smaller lines are
required (or perhaps just installed.) In any event, the suggestion locally had been
that to upgrade the compressor/condensor units, all the A/C components needed to
be replaced, end-to-end.

I haven't felt like dealing with any more of the 'oh, just change it out' crowd, so I
haven't been calling around since my earlier posts and have nothing further to report
on that score.